Seat heather

[chiccokaiser1]

Hi, passenger seat heather works great while driver's doesn't work at all now. Lights on on door panel works.. can't see from user's manual what fuse I should check. Is it a resistance problem or what?? Can anybody guess?
Thanks

[Tech II]

Could you give us the year?

From my experience, it's usually one of the heater pads.....they are wired in series so if one opens, they both go out.....like old Christmas tree lights....

It was a stupid design by GM, should have been wired in parallel, that way if one worked and the other didn't you immediately knew it was the pad......by being in series, you don't know if it's a switch, module, or which pad is open...

If you have access to a wiring diagram, disconnect harness to the module and test the series circuit of the pads with an ohm meter...if you get OL, one of the pads is bad(open circuit)....replacement is both pads.....

[chiccokaiser1]

Yes, if they are in series you are definitely right. My car is a 2002. Do you know if it is a pain to replace pads if that will be the case??
Thank you!

[Schurkey]

I acknowledge that "anything can happen", but the most-common cause is the seat-bottom heater having an open circuit.

The pre-failure symptom is that the heater develops hot-spots. The whole heater works, but one place in particular is REALLY HOT.

You'll find the seat foam is burned where the heater open circuit is, and where the hot-spot was.

The job is not "horrible", but it is a pain in the ass. The hog-ring plier that Dorman includes with their aftermarket seat heater is pretty lame.

The way I remember it, I removed the seat back in-the-car, then lifted the seat bottom out by itself for repair.